In the wake of Hurricane Sandy, there have been a flurry of ideas on how to deal with the prospect that storms of such magnitude may no longer be once-in-a-lifetime events but the most visible manifestation–if you’re not a polar bear–of the havoc wreaked by climate change.

Seawalls. Levees. The kinds of things the Army Corps of Engineers typically builds to protect low-lying places like New Orleans just aren’t feasible for a place like Manhattan, says Stephen Cassell, the cofounder of New York’s Architectural Research Office. “It’s hard to predict how bad climate change will be,” Cassell says, noting that Sandy’s devastating surge was nearly 14 feet, which wasn’t even the worst-case scenario. “What if we build a barrier and the surge goes beyond that?”

How might two-tiered taxation work? In New York, land and improvements in residential areas are subject to an 18.6 percent property tax.Thus, land with a taxable value of $10,000 would be taxed $1,860, and improvements with a similar taxable value of $10,000 would owe another $1,860, a total of $3,720. Under a two-tier system, the tax rate for land could jump by, say, 50 percent, while the rate for improvement could be halved.In that case, the owner would pay $2,790 in land taxes and $930 for improvements — keeping the total to $3,720.

But here’s the payoff: The owner’s tax bill under that scheme would climb another $2,790 if he purchased a second lot with a taxable value of $10,000 — but by only $930 if he used that money toward building.Thus, hoarding would be discouraged; development encouraged.

The two-tier property tax has a proven record of success. In 1979, Pittsburgh began taxing land at a rate six times higher than improvements. In the ensuing decade, building permits increased by 70.4 percent.